Field
Apparatuses and methods consistent with exemplary embodiments relate to controlling power consumption in a standby mode.
Description of Related Art
An electronic apparatus including a display apparatus, such as a television, may be provided with a power supply for supplying power needed for operations. The electronic apparatus may have a plurality of power modes, and may enter a standby mode, in which power supplied to some elements is shut off to decrease power consumption. For example, the power may be shut off after a predetermined time elapses without any operation.
When an electronic apparatus is in standby mode, the system may need standby power for performing the minimum operation. To accomplish this, the electronic apparatus may have a power supply (hereinafter, referred to as a ‘standby power supply’) for supplying power in a standby mode.
FIG. 1 is a view showing a related art power supply.
Referring to FIG. 1, a power supply 10 operates as follows.
If alternating current (AC) power is supplied, a bridge rectifier circuit 11 converts an AC into a direct current (DC). Under control of a switching controller 12, a switching element (e.g., a field effect transistor (FET) 13) performs a switching operation, and DC power is supplied from a primary side of a transformer 14 to a secondary side in response to the switching operation.
The power supplied to the secondary side of the transformer 14 is output as the DC power to the system of performing the operations of the electronic apparatus via a rectifier D1 and a smoothing capacitor C1 of a constant-current controller 15.
The power in the secondary side of the transformer 14 is controlled, i.e. regulated, by a voltage regulator 15a, a first reference resistor R1, and a second reference resistor R2, of the constant-current controller 15, and fed back to a switching controller 12 at the primary side of the transformer 14 via a photo-coupler. The voltage regulator 15a receives a bias current for operation through a bias resistor R3.
The power supply 10 of FIG. 1 may operate in a burst mode so as to decrease loss caused by a switching operation under a low load condition such as a standby condition. In the burst mode, the power supply 10 operates the switching element 13 in accordance with a preset burst period, stops the switching operation in a predetermined section (e.g., an off-section) corresponding to the burst period, and prevents power loss due to unnecessary switching operations. Here, the burst period may be previously set from milliseconds (ms) to a long period for achieving ultra-low standby power, e.g., seconds (s).
However, a related art power supply 10 may consume power by a voltage regulator 15a, first and second reference resistors R1 and R2, a bias resistor R3, etc. even in the off-section in which the switching operation is not performed. Specifically, referring to FIG. 1, voltage charged in the smoothing capacitor C1 is supplied to and consumed by the voltage regulator 15a, the first and second reference resistors R1 and R2 and the bias resistor R3 in the off-section.
Therefore, the power loss continuously occurs in the standby mode regardless of the burst operation, which causes a problem of increasing the standby power.